The applicant of the present patent is at the same time titleholder of the spanish utility model No. 289,848 and patents Nos. 8803635 and 8902872.
The above mentioned documents refer to various support bars which the applicant of the present invention has been developing. The utility model No. 289,848 specifies the constitution of a support bar formed by multiple thin, flat strips, contiguous and packed together, attached to each other at one of their ends, and having the property of transverse elasticity due to which they tend to recover their initial position when submitted to a force at right angles to their larger face. Strips are strapped together by means of one or more flexible wrapping ties which keep them firmly juxtaposed one to another in order that, should the bar bend across one of its larger faces, a displacement under friction occurs between the thin strips, which displacement allows the bending and/or arching of the bar whilst braking and hindering its spontaneous return to its initial position.
The patent No. 8803635 refers to a support bar formed from a chain whose links, articulated one with another, are positioned between two flexible longitudinal strips, provided in trasversal direction with elasticity which tends to return them to their initial position when submitted to a force at right angles to their larger faces. The strips are firmly held to the two opposing faces of the link chain by means of a layer, or covering, of plastic material applied around the chain, and by a flexible and resistant tape, with a high degree of longitudinal rigidity, which is then applied to the covering, or layer, described above with the objective that, should a force be applied along a line more or less at right angles to the larger faces of the strips, the bar will bend and hold itself stable in this position without returning spontaneously to its initial position. The bar is subsequently given an external covering as embellishment.
The patent No. 8902872 describes a support bar formed by a prismatic rod which consists of rigid sections which alternate with flexible sections which are achieved by a plurality of deep transverse depressions. This rod is positioned between two longitudinally flexible strips which tend to recover their initial position on being subjected to a force at right angles to their larger faces according to characteristics already defined in patent No. 8803635. The above described assembly, in like manner to the bar described in the aforementioned patent No. 8803635, is enclosed in a wrapping which consists of an inner layer of plastic material and a flexible, resistant, tape having a high degree of longitudinal rigidity in order to allow the bending and/or arching of the bar in the previously described flexible regions.
Experience has shown that the practical embodiment of the object of the cited patents presents a number of drawbacks. For example the support bar which is the object of utility model No. 289,848 does not have sufficient flexibility and recuperative capacity to ensure the movement which it may undergo during its use.
The use of a flexible, resistant and longitudinally rigid tape, wrapped around the bar core, as with the bars which are the object of the patents Nos. 8803635 and 8902872, does not resolve this problem since in this case the strip loses the capacity to keep its stable position after a certain number of flexions of the bar, and yields when a given force or weight is applied to it.
If the pressure with which the tape is wrapped around the bar core is increased the frictional force created between the flexible strips becomes excessive to the point that such strips may break after a limited number of flexions of the bar.
In the case of the version of the bar which is the object of the patent No. 8902872 the flexible regions of the bar, formed by deep depressions, break after the bar has been subjected to flexion movements for some time.